Somebody recently linked to one of my earlier posts on Galileo and as I flew over the contents I was reminded of a promise that I had made there that I would discuss Galileo’s failure to acknowledge Tycho Brahe’s geo-heliocentric model of the universe in his Dialogo. This post also has a second purpose and that is to at least partially explain why I don’t accept Thomas Kuhn’s concept of the paradigm shift in the history of science.

In his most notorious book, Dialogue Concerning the Two Chief World Systems, Galileo Galilei presents what could best be described in terms of modern dramatics as a cosmological Celebrity Death Match featuring in the red corner the aging reigning champion the geocentric system of Ptolemaeus weighed down by a 1400 hundred year old Greek gravitas, seconded by the Aristotelian Scholastic philosophy and in the blue corner the sprightly young challenger the heliocentric system of Copernicus buoyed up by the scintillating new telescopic discoveries and seconded by the new philosophy of GG in person. Although presented with far less polemic and showmanship this is the same story that was told by Thomas Kuhn in his The Copernican Revolution, the historical study that led him to develop his concept of the paradigm and the paradigm shift. According to Kuhn a scientific discipline is defined by its paradigm under which the participants in that discipline work, doing normal science, until enough unsolved problems within the discipline have accumulated, which leads to a crisis and in a revolution the old paradigm is replaced by a new one. This description ignores the very major problem that Kuhn never really succeeded in clearly defining what a paradigm is and assumes for the sake of argument that it is clear. Kuhn’s prime example for a real paradigm shift in the history of science was the Copernican Revolution, according to him the Ptolemaic astronomy found itself in a deep crisis in the High Middle Ages and was overthrown in a revolution by the Copernican model, like Galileo he saw this as a two way competition between the systems. However both Galileo’s and Kuhn’s presentations fail on the fact that the astronomical and cosmological transition in the 17th century more resembled a Royal Rumble than a straight one on one fight. As Galileo and the other early telescopic astronomers first made their discoveries at the end of the first decade of the 17th century there were not two competitors in the ring but a whole handful weighing in for the honour of explaining the mysteries of the universe.

Before returning to my cosmological Royal Rumble and presenting the individual participants I want first to deal with another of Kuhn’s false claims, namely that the Ptolemaic system was in crisis. The Ptolemaic system relied on a sophisticated geometric model of deferent circles, epicycles, eccentrics and equant points to describe the motion of the planets and to be able to predict their positions for any given time. Kuhn claimed that this system was highly inadequate and that over the years Islamic and mediaeval European astronomers had added epicycles on epicycles to the system in an attempt to make it work and that by the 16th century it had become hopelessly confused and in danger of collapsing under its own complexity. This is the crisis that according to him called the Copernican model in to existence and led to the revolution in which the new paradigm replaced the old. Unfortunately for Kuhn this is simply not true. The Ptolemaic model had been, over the centuries, actually improved and simplified and was actually surprisingly good at doing what it should do that is predicting the positions of the heavenly bodies for use in astrology, cartography and navigation. Having said that one does have to admit that those predictions were far from perfect, a product of the limitations of accurate observations in antiquity when the raw data for the model was accumulated and secondly the errors that had crept into that data over the centuries in the process of copying and translation astronomical manuscripts. The problems caused by these inaccuracies were well known the members of the first and second Viennese Schools of mathematics who set out to renew and reform mathematical astronomy beginning in the middle of the 16th century. Peuerbach and Regiomontanus produced new astronomical textbooks that were among the earliest printed science books, which served to educate a new generation of mathematical astronomers, including Copernicus, who set out to improve the accuracy of their discipline. It was in the pull of this general movement that Copernicus produced his new model and we don’t actually know why he did so. At first his book was greeted very favourably, not for the cosmology but for the mathematical astronomy, in the hope that it would provide more accurate figures for the planetary positions. Unfortunately as it was largely based on the same raw data this hope soon proved an illusion with in some cases the figures calculated using Copernicus’ model being even more inaccurate than those generated by the Ptolemaic model. It should also be pointed out that the Copernican system was more complex and contained more circles than the then prevailing geocentric model.

Inspired by Copernicus’ work and disgusted by the inaccuracies of both models Tycho Brahe set out to collect a new set of raw data on which to base astronomical calculations. Rejecting Copernicus’ cosmology on both astronomical and religious grounds he also developed a third model his geo-heliocentric model in which the planets except for the earth and the moon all revolved around the sun, which revolved around a stationary earth. This model retained all of the new explanatory power of the Copernican model without the very real problems generated by a moving earth. This model was actually preceded by the almost identical model of Nicholas Reymers Bär, known as Ursus, which although it had the earth in the centre gave it a daily or diurnal rotation instead of having the sphere of the fixed stars rotate daily.

As you can see we already have the first four contestants for our Royal Rumble and if we proceed to 1609 and the eve of telescopic astronomy we see that they did not enter the ring alone. For some reason, that as far as I know nobody has really researched, the astronomers at the end of the 16th century were more prepared to accept a daily rotation of the earth around its own axis than an annual rotation of the earth around the sun. In 1600, with the publication of his De magnete, William Gilbert proposed a Ptolemaic geocentric system with diurnal rotation, which was very popular and was responsible for many people adopting the Ursus system rather than the pure Tychonic system when they finally abandoned a geocentric model. Also available and although not wildly popular was the Egyptian or Heracleidian model from antiquity in which only the two inner planets, Mercury and Venus, circled the sun which along with the other planets, Moon, Mars, Saturn and Jupiter, circled the earth. This model could, like the Tychonic model that was modelled on it, explain the phases of Venus discovered with the telescope that proved fatal for the geocentric models of Ptolemaeus and Gilbert. The last contestant to enter the ring was the fledgling of the group, and the eventual victor, Kepler’s world system as first proposed in his Astronomia nova from 1609. Galileo, for reasons that to this day remain unknown although much speculated upon by historian of science, completely ignored Kepler’s work although it offered better arguments for heliocentrism than anything he had produced himself. Kuhn like many historian treats Kepler as if he were just a minor amender of Copernicus and therefore not relevant however a survey of the astronomical and cosmological discussions in Europe in the first half of the 17th century show that Kepler’s system, the elliptical astronomy, was regarded as a separate system and a competitor to Copernicus’ system.

If you have been keeping count you will know that we have seven contestant in the ring squaring off for the cosmic championship, Copernican heliocentricity, Ptolemaic geocentricity, Gilbertian geocentricity with diurnal rotation, Tychonic geo-heliocentricity, Ursian geo- heliocentricity with diurnal rotation, the Heracleidian model and last but anything but least Kepler’s elliptical heliocentricity. All of these model or systems had their supporters and detractors in the early decades of the 17th century a fact that gives a very different picture to the one presented by Galileo or Kuhn in their works. We don’t have Galileo’s two way fight with the scales stacked in favour of Copernicus or Kuhn’s Copernican paradigm ousting the Ptolemaic one in a clean revolution what we have is a plethora of astronomical models all jostling for centre stage.

Found too lightweight to really compete the Heracleidian model was the first to fly over the top rope and out of the contest. Crippled by the telescopic discovery of the phases of Venus the two geocentric models, with and without diurnal rotation, soon followed but both went out fighting as illustrated by the famous frontispiece in Riccioli’s Almagestum novum from 1651 that shows Ptolemaeus lying on the floor and seemingly out for the count but defiantly claiming, “I will arise again”.

Riccioli’s book, which lists and discusses six different models of the universe, is a strong piece of evidence for the competition described here. The Copernican system sort of just faded away in the face of the superiority of Kepler’s elliptical system. By the early 1630s there were only three serious contenders still battling it out for the cosmic championship, Kepler’s and the Tychonic systems with and without diurnal rotation. At this point in the contest the Tychonic system with diurnal rotation was well ahead on points. This is the point at which Galileo published his Dialogo in which he presents a contest between the Copernican and Ptolemaic systems blithely ignoring the fact that both were effectively already out of the running. His book proved popular amongst literati who were not astronomers who enjoyed his very obvious polemic writing skills but contrary to popular opinion it didn’t play a significant role in the contemporary scientific discussion.

By around 1660 Kepler finally carried the laurels in the contest for two different reasons. As already mentioned astronomical models were judged on their ability to predict the position of heavenly bodies at any given time for various applications. In 1627 Kepler published his Rudolphine Tables based on Tycho’s data and on his own system. These tables of planetary positions proved so superior to anything and everything that had existed previously that it convinced the vast majority of astronomers of the superiority of Kepler’s system. Also as Fontanelle explained in his Conversation on the Plurality of Worlds from 1686, a popular presentation of a Cartesian, elliptical heliocentric model, the Tychonic systems had been abandoned around 1660 because of their complexity in comparison to the Keplerian one, an application of Occam’s razor.

It should be pointed out that the transition to Kepler’s system was not all plain sailing. His replacement of the perfect Platonic circles with ellipses was accepted without any major resistance and his third law connecting the radii of orbits to their periods in a fairly simple mathematical formula was also accepted with joy by an astronomical community convinced of a mathematical regularity in the laws of nature. However his second, the area law, was almost universally rejected as ungainly and ugly, as was his highly dubious mathematical proof of the same. A strong debate raged through the mathematical community throughout the 17th century with various participants, most notably Ismael Boulliau and Seth Ward, offering simpler and more elegant alternatives, which unfortunately didn’t work. This problem was first solved in 1672 when Nicolas Mercator provided a new correct mathematical derivation of the area law. Shortly thereafter Newton subsumed the Keplerian system in his much wider ranging Principia and the show was seemingly over.

Defenders of Kuhn might argue that with Newton the paradigm shift had taken place. Two things speak against this hypothesis firstly that which I have described resembles that which Kuhn describes as the pre-paradigmatic phase of a science that is the phase before a discipline has developed its own paradigm and is therefore not yet a scientific discipline, however he claims that astronomy was a discipline with the Ptolemaic geocentric astronomy as its paradigm. Secondly even following the publication of Newton’s Principia we still don’t have a single, dominating. unchallenged model. Both the Cartesians and the Leibnizians challenged Newton’s model because it was not mechanical with its action at a distance concept of gravity and the Cartesians fought a rearguard action supporting Descartes’ vortex system against Newton’s gravity until deep into the 18th century. Leibniz also challenged Newton’s assumption of absolute time and space, proposing a relative system instead; a challenge that would with time lead to the refutation of Newton’s system but that as they say is another story.

Proof of the contest between a multiplicity of astronomical systems in the 17th century can be found not only in Riccioloi’s Almagustum, as already mentioned, but also in the astronomical section of Robert Burton’s The Anatomy of Melancholy first published in 1621 and then in many expanded edition over the next ten years and in the work of Athanasius Kircher as well as in numerous books and pamphlets published by the participants. In my opinion this evolution of the astronomical and cosmological systems in the 17th century gets ignored largely because it’s too messy to be pressed into a neat philosophy of science model of scientific progress. Why sacrifice academic elegance for the messy reality that is real history?

46 responses to “Galileo’s great bluff and part of the reason why Kuhn is wrong.”

Fascinating. I had no idea there were so many co-existing models. I think if anything, astronomical history typically combines Copernican-Keplerian into a single model whereas according to what you wrote, people at the time did not regard them as the same. Typical simplistic history of science.

So overall, was Galileo’s major contribution the popularization of a heliocentric model, and not the bulk of the astronomical science?

Re: Kuhn; given this more detailed history, would Kuhn just consider this whole era a “crisis”? That is to say, astronomy was not in its pre-paradigmitic phase, but had matured enough to notice anomalies in its models and have its ensuing crisis phase.

Regarding the Newtonian era, were the counter-arguments of the Cartesians and Leibnizians popular within the scientific community?

Thanks for explaining the situation as it was, I didn’t realise that there where so many competitive ideas around at the time.

I suspect that GG may be lauded so much and the others downplayed for reasons other than simple ignorance.
Rather like the strange belief that people thought the earth was flat when Coulumbus went a sailing.

Excellent post. On a loosely related topic, I wonder if you or your loyal readers can clear up something which has been bugging me for years:

In 1985, as part of a History & Philosophy of Science course at Durham University (UK), I wrote an assignment discussing an old astronomical/philosophical paper in the rare books room in one of the university libraries. The paper argued that we can infer some force (e.g. God, or Mr Newton’s new-fangled Gravity) must have placed the stars where they are because they are clumped together, rather than being spread randomly across the heavens. Another (slightly later) paper I read debunked this argument by explaining that the original paper’s author had an incorrect understanding of what constitutes a random pattern of dots (i.e. he believed that what I referred to as a polka-dot pattern is random, whereas it is anything but).

Unfortunately, I cannot remember the names of the authors of the two papers in question, which is what has been bugging me for years. Does anyone know their names?

The answer to your question would interest me too. The situation described is anything but trivial, it is in fact an important part of any modern theory of cosmology to explain why matter is not evenly distributed throughout space but clumped.

As I understand his paper on the origin of the solar system, Kant recognized that a truly random distribution of particles implies a certain amount of clumping because a perfectly homogeneous distribution would be exceedingly unlikely. Kant evidently subscribed to the Mao’s maxim in the Little Red Book: “Nothing develops absolutely evenly” if not Heraclitus’ dictum that even the sacred barley water separates. A lot of the speculations of Stuart Kaufmann have a similar logic: disorder has a limit because at some point one can only increase disorder in one respect by increasing order in another.

I am interested to know why you class the Ursus system as a seperate system to Tycho’s? I would place them together, as I would argue that Ursus plagurised Tycho’s system. For an interesting study on this and how Tycho got Kepler to publish a defence of Tycho and his precedence in coming up with the model read Nicolas Jardine’s ‘The Birth of History and Philosophy of Science.’ Having studied Tycho I would say that Nicholas Ursus did in fact copy Tycho on his visit to Tycho’s island of Hven. The repercussions of this was a series of highly offensive polemic tracts between the two. This I think is a significant point of fact: that whilst Ursus published his model first he was not the first to come up with it.

Whether your model attributes diurnal rotation to the earth or not is within an astronomical or cosmological description of the solar system far from being a trivial detail and therefore a Tychonic system with diurnal rotation is a separate system to one without. This is not just a theoretical point as such systems were treated as competitors in the 17th century.

It is also irrelevant to this consideration as to whether the geo-heliocentric system with diurnal rotation was derived from Tycho’s system or invented independently as Ursus, John Craig and Helisaeus Roeslin all claimed to have done. A not unlikely claim as Tycho’s system is only a logical extension of the Heracleidian system which was very well known and highly popular in the Middles Ages.

On the subject of Ursus’ supposed plagiarism of Tycho the known facts are anything but conclusive. On my reading Kepler (and also Jardine) remain fairly neutral on the subject. Edward Rosen in his “Three Imperial Mathematicians” sides with Tycho against Ursus but as far as I can see the only evidence he offers are his own prejudices. Robert Westman and Owen Gingerich in their “The Wittich Connection” argue very convincingly that both Tycho and Ursus plagiarized Wittich who first developed but never published the system.

I apologise for my oversight. I had forgotten that the two systems differed in terms of diurnal rotation. For some reason I had thought that Tycho had held that the earth rotated. But you are right it is a significant difference. I also agree that it seems more likely that neither Tycho or Ursus, what I think made Tycho stand out was the fact that he had, at least felt that he had evidence that established his model as true from his vast body of data.

Thank you for the references to the Rosen, Westman, and Gringerich articles. I shall have to read them, as they have escaped my attention.

Something I have just remembered regarding your point about the fact that the Astronomers were more prepared to accept the earth rotating then the earth moving around the sun. Tycho in a passage (I paraphrase) says that he is against it because the earth is such a big and sluggish body that too provide the energy to move it would be gigantic, and where would such a massive amount of energy come from? The lack of answer to this caused him to reject it. Whilst this shows his reason for rejecting heliocentricism, I think the argument would also apply for preferring diurnal rotation, as this would require less energy then having the earth move through space. I would note that this is my instinct and memory I would have to go back and look through my notes and research some more. But I think it would make an interesting study.

I would also like to say that this is an excellent post. It has provoked a lot of thoughts that fit in with my own research. What I find interesting is why it was that the geo-heliocentric system was rejected, when the findings of Galileo would have fitted into both systems? It was not clear which system was correct. At the moment I am tracking the references to Tycho, Galileo, and Copernicus through the seventeenth century to try and understand the mess of the cosmological battle and why they accepted one over the other. I also wonder why it is that we have inherited a caricature of the copernican revolution rather then the complex battle you describe? It can’t have been down to just Kuhn, so what created the perception that the shift was so clear?

Re “where would such a massive amount of energy come from? The lack of answer to this caused him to reject it. Whilst this shows his reason for rejecting heliocentricism, I think the argument would also apply for preferring diurnal rotation, as this would require less energy then having the earth move through space.”

You’re using what Newton taught us about how objects falling around each other (orbiting) behave, which obviously Tycho simply didn’t know. If the idea predates Newton, I don’t know where.

“Part of the reason why Kuhn is wrong,” indeed. The critique needs to be extended to really touch on what Kuhn actually wrote. I cannot find a reason in his book why there should never be multiple paradigms in existence. However, Kuhn is unclear about when a theory becomes a paradigm. If there are multiple models in existence, does that mean that they are all paradigms, or just rival theories? “Philosophers of science have repeatedly demonstrated that more than one theoretical construction can always be placed upon a given collection of data. History of science indicates that, particularly in the early developmental stages of a paradigm, it is not even very difficult to invent such alternatives.” (The Structure of Scientific Revolutions, p. 76, end of chapter VII).

The concept of scientific communities was important to Kuhn. If it can be shown that these models did not divide the community, then this is a serious problem. Different paradigms should be incommensurable, but if a normal debate within a singular community was able to solve the issue with a methodology upon which all could agree, then the difference between normal science and paradigm shift has become too muddy to hold water for this case. So it is in the communication within the scientific communities that I think the answer lies.

One needn’t suppose a unitary, logical, consistent paradigm, but debate is impossible if the participants do not share at least SOME ideas/presuppositions/methods.

Perhaps Kuhn’s paradigm is like structuralist accounts of culture in anthropological theory: monolithic, inescapable. Anthro theorists these days are more likely to see “culture” as an assemblage of loosely-linked notions and practices, which need not be monolithic at all.

The problem with Kuhn’s incommensurability thesis is that it apparently postulates that paradigms share no ideas/presuppositions/methods, according to some interpretations. However, Kuhn does suggest there are some values that make scientists rationally choose between paradigms.

But when you say that debate is impossible, you have touched upon the fact that it does look like that in some debates. When scientists are truly opposed, they do tend to talk ‘through’ eachother – communication has become very difficult. Kuhn would predict that they use terms in incommensurable ways. Perhaps that is one way to test his theory, something I think is generally very difficult.

I don’t know anything about structuralist theories, but wouldn’t call paradigms ‘monolithic’. You may find Ernan McMullin’s 1993 paper, ‘Rationality and Paradigm Change in Science’, interesting. It discusses rationality in Kuhn’s work from the perspective of scientific realism and also argues for ‘flexible’ definitions of paradigms, shared by different communities and changing on different timescales (par. 2).

a) Did the Heracleidean system have a rotating Earth or a stationary one?

+ + +

b) The dual motions of the Earth were rejected because:

i) Revolution around the sun would produce observable parallax in the fixed stars. No such parallax could be seen.

ii) Rotation of the Earth would mean objects at the top of a tower would have greater eastward velocity and so when dropped would fall east of the plumb line. Although Galileo himself proposed the experiment, there is no evidence anyone carried it out until ca. 1790.

In Popperian terms, heliocentrism was “falsified,” which indicates the flaw in Popper (as well as his disciple Kuhn).

The problem with i) was that the stars were *much farther away than their relative brightness and apparent diameters suggested. [cf. the Duhem thesis: you can never assume just one hypothesis.] Calandrelli observed parallax in a-Lyrae in 1803 [before Bessel].

Regarding ii), Guglielmini dropped weights from the tower of Bologna between 1789-1792, dropping them down the center of the spiral staircase inside the tower (to avoid windage).

At this point, the dual motions of the earth were confirmed empirically (vs. having cooler math and a neat gravity story).

You are quite right in saying that the failure to detect parallax and the Coriolis effect were both stumbling stones in the acceptance of heliocentricity, there were however others.

As several Popperians have pointed out on numerous occasions all scientific theories are born falsified but that some potential falsification can be accepted and ignored for the time being. This led Lakatos to develop his theory of Scientific Research Programmes which is modified falsificationism.

Kuhn was not a disciple of Popper!

Hooke amongst others tried to detect the Coriolis effect experimental more that 100 years before Guglielmini.

The annual rotation of the earth was confirmed in 1725 by Bradley’s detection of stella aberration.

The diurnal rotation was confirmed indirectly in the 1750s by the determination of the earth’s shape as an oblate spheroid. Both Struve and Henderson measured stella parallax before Bessel but he published first.

Thanks for the reply. The Wiki entry claims a rotating earth for Heracleides, but that didn’t seem right. A good job presenting the confused scientific situation; too many Late Moderns, looking back at the past with the hindsight of the present, don’t see the very real scientific objections, doubts, and potholes.

I recollect that Kuhn had issues with Popper, but Popper was the necessary prerequisite for Kuhn. Both seem to have been deeply hostile to scientific certainty. I should not have stated it in so careless a fashion.

Bradley’s stellar aberration was a very slight effect, variable, and required specialized instruments. Well enough known to those who knew well enough, it was not sufficiently empirical to convince non-specialists, and did not come to the attention of the Roman authorities. (I have in mind the lifting of the ban with Settele’s astronomy textbook – which makes Calandrelli’s probable error deeply ironic.)

Bradley’s aberration was know to the Roman authorities and was one factor in the lifting of the ban on the holding and teaching of heliocentricity in 1755! Settele’s textbook is a case of a local inquisitor reminding the church that they still needed to do some formal clearing up in their regulations.

Heracleidian, perhaps, but not the system of Heraclides. From James Evans’ The History and Practice of Ancient Astronomy, p.349:

Chalcidius attributes the system to Heraclides of Pontos (forth century B.C.) — but he is clearly mistaken, as Heraclides lived before the invention of the epicycle theory.

referring the reader to Bruce Eastwood, “Heraclides and Heliocentrism: Texts, Diagrams, and interpretations”, Journal for the History of Astronomy v.22 (1992) p.233-260, for a “detailed refutation of the attribution”.

Evans adds,

Perhaps Chalcidius attributed this view to Heraclides because he was known to have held another unorthodox astronomical opinion: the daily rotation of Earth on its axis.

and he devotes about a page (p.35-36) to that attribution, arguing that “The earliest philosopher who unambiguously and undeniably taught the rotation of the Earth on its axis was Heraclides of Pontos”.

Good for him. If his theory isn’t scientific, then we can ignore it. If it is incorrect, we can ignore it. (This is my view.) If it is correct, then we can ignore it—since it is merely a fashion which will be replaced by the next paradigm.

I agree with you that Kuhn paints too simple a picture of the geocentric-heliocentric transition. However, it is worth pointing out that he devotes nearly five pages of The Copernican Revolution to the Tychonic system, mentions that two other astronomers put forward similar systems, says that almost all the more erudite seventeenth-century Ptolemaic astronomers retreated to the Tychonic system, and remarks in the bibliographic notes that the popularity of the Tychonic system is often underestimated.

Nor is the Rumble you describe inconsistent with Kuhn’s ideas in Structure. At the top of p.83 (2nd and 3rd eds.) he describes the response to a crisis:

…more and more of the attacks upon [the problem] will have involved some minor or not so minor articulations of the paradigm, no two of them quite alike … Though there is still a paradigm, few practitioners prove to be entirely agreed about what it is.

Of course, this reconciliation of Structure with your Rumble relies on ‘paradigm’s extraordinary elasticity.

Very intelligible and informed report of historical facts not taken into consideration by Kuhn. In the context of Mechanics the question if earth or sun is at the center is meaningless. The only sensible staments to be done are:
1. the two bodies move one respect to the other;
2. if you put the earth at the center the handling, efficiency and pregnancy or syntethicity – whatever you like – of the description are more complicated as compared to considering the sun at the focus of an ellypse;
3. if you introduce an attractive force between the bodies inversely; dependent on the square of the distance an elliptical orbit is foreseeable.
Kuhn analysis fails to present or even mention such a situation
Back to Kuhn, my main criticism is based on fthe ollowing remarks:
a. much talking of paradigm without definig what it is meant by paradigm (an example is in the comment by Michael Weiss which is fully acceptable but demands for a peculiar interpretation of what a paradigm is)
b. the so called revolution is more an evolution since previous results are not lost, but simply expanded (when new results give generalization like relativistic vs. newton mechanics which is still valid for motion at speed low as compared to light speed)
Bad use by many post modern philosophers has been made of Kuhn (overestimated) considerations, first interpreting the capacity of physics of expanding and deepening human knowledge of world as a proof of being solely an arbitrary or fantastic product of mind and secondly calling science unreliable, welcoming a methodology whatsoever as acceptable and justifying hereafter an assault against science still active and still creating very negative outcomes in particular against technology..

I really liked this post, so I spent some time figuring out the various systems. I also looked closely at the front page of Riccioli’s Almagestum novum above, but I just couldn’t figure out the right-hand system depicted there. It didn’t fit in with any of the seven systems discussed. But it turns out that the Wikipedia page on Riccioli actually describes it as something which must be system number eight as far as I can understand.

Quoting from Wikipedia: “Frontispiece of Riccioli’s 1651 New Almagest. Mythological figures observe the heavens with a telescope and weigh the heliocentric theory of Copernicus in a balance against his modified version of Tycho Brahe’s geo-heliocentric system, in which the Sun, Moon, Jupiter and Saturn orbit the Earth while Mercury, Venus, and Mars orbit the Sun.”

Mars is not included in the Tychean and Ursus models as far as I know, so is it a model no. 8?

While I also argued against Kuhn somewhere, I think semantics is not your strong point, and you might not understand his meaning of “crisis” (I also object to your tone here). It doesn’t mean that anyone is actually in despair over their results, it means that a system’s dogmatic retrictions become increasingly disintegrated by new discoveries or possiblities of thought, such as the discovery of other moon’s circling a giant planet, and the direct possibility that follows from there for an argument of a similar case with the earth etc. … Or when the church say, is undecided about its adaptions, except that it doesn’t tolerate any statements of “facts”, its own “facts” are (disacknowledgedly) also in scientific doubt.

Your interpretation of “crisis” certainly doesn’t fit with anything I’ve ever read in Kuhn on the subject. Also Kuhn saw the Ptolemaic system in crises before Copernicus developed his heliocentric system and not when Galileo and Marius discovered the moons of Jupiter. In fact Kuhn argues that that crises was the motivation for Copernicus’ new developments.

I don’t know what you mean instead. But I have only read Kuhn’s theoretical work The Structure of Scientific Revolutions. Kuhn had a very open idea of “paradims”. He could emphasize different arguments according to counterargument, example or the prevailing theme of the chapter. Yes, he may have spoken at some point of shocks and surprises, and inabilities to explain. But he also was explicit that they always potentially could be explained at some point or in some way (and therefore someone could be totally at ease about the whole issue, things could even be ignored and forgotten). However it is when new ideas come up and can be logically or observationally explored that the true strucural point of crisis can be named. I think he is fairly clear about that one piece.

If that is some slight adaption of some verbatim version, I would maintain that this still remains an argument to be made between systems.